Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
  • F01D5/288—Protective coatings for blades
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
  • C23C10/28—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
  • C23C10/34—Embedding in a powder mixture, i.e. pack cementation
  • C23C10/52—Embedding in a powder mixture, i.e. pack cementation more than one element being diffused in one step
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
  • C23C10/28—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
  • C23C10/34—Embedding in a powder mixture, i.e. pack cementation
  • C23C10/52—Embedding in a powder mixture, i.e. pack cementation more than one element being diffused in one step
  • C23C10/54—Diffusion of at least chromium
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
  • C23C16/32—Carbides
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
  • C23C16/42—Silicides
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/10—Metals, alloys or intermetallic compounds
  • F05D2300/13—Refractory metals, i.e. Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

• the invention relates to parts coated with a protective coating and methods for manufacturing such parts.
• niobium-based alloys appear to be particularly promising in order to replace or be used in addition to existing nickel-based superalloys. These different alloys have the advantage of having melting points higher than existing superalloys.
• niobium-based alloys can also advantageously have relatively low densities (6.5-7 g / cm 3 compared to 8-9 g / cm 3 for nickel-based superalloys). Such alloys can therefore advantageously make it possible to significantly reduce the weight of turbine engine parts, for example high-pressure turbine blades, because of their low density and their mechanical properties close to those of nickel-based superalloys at similar temperatures. of 1100 ° C.
• the niobium-based alloys can generally comprise numerous additive elements such as silicon (Si), titanium (Ti), chromium (Cr), aluminum (Al), hafnium (Hf), molybdenum (Mo), or tin (Sn), for example.
• These alloys have a microstructure consisting of a matrix of niobium (Nb ss ) reinforced by dissolved additive elements in solid solution. This phase ensures acceptable toughness of low temperature alloys.
• Nb ss niobium
• intermetallic precipitates often silicides of refractory metals whose composition and structure may vary according to the additive elements (M 3 Si, M5S13).
• the present invention aims, in a first aspect, a method of manufacturing a part coated with a protective coating comprising the following step:
• a protective coating on all or part of the surface of a workpiece, the part comprising a refractory alloy comprising a niobium matrix in which inclusions of metal silicides are present, the protective coating being formed by a carburizing process in box from a cementation comprising: i. a mixture A (Nb x Tii -x) 3M3CrSi6 and M 0, 0 6Cr, 4Si where M is Fe, Co or Ni and x is between 0 and 1, or
• mixture A denotes a mixture of (Nb x Tii -x) 3M3CrSi6 and M 0, 6Cr 0, 4 Si where M is Fe, Co or Ni and x is between 0 and 1.
• mixture B denotes a mixture of M'Si, NbSi 2 and Nb 4 M ' 4 Si7 where M' denotes Fe, Co or Ni.
• the present invention advantageously makes it possible to form protective coatings on niobium-based parts capable of developing protective oxide layers in order to improve the oxidation resistance of these parts without affecting their mechanical properties.
• the case cementation process advantageously makes it possible to treat parts having complex geometries, to deposit on them several elements in a single step and to obtain a protective coating of uniform thickness.
• the process according to the invention is based on the choice of particular mixtures of donor alloys in the cement used (mixtures A and B mentioned above). These mixtures advantageously make it possible to obtain protective coatings which very significantly improve the oxidation resistance of the treated parts.
• the part may consist of a refractory alloy comprising a niobium matrix in which precipitates of metal silicides are present.
• the protective coating formed may comprise a plurality of distinct phases, these phases may be in the form of layers superposed with each other.
• the formation of these phases is governed by the solid state interdiffusion of the deposited elements and the constituent elements of the substrate.
• the protective coating formed comprises Nb, Fe and Si.
• several phases of the protective coating may each comprise Nb, Fe and Si.
• the protective coating formed comprises Nb, Co and Si.
• the coating each protector may have Nb, Co and Si.
• the protective coating formed comprises Nb, Ni and Si.
• several phases of protective coating may each comprise Nb, Ni and Si.
• the cement may comprise a mixture B and before the start of the case cementation process:
• the ratio (mass of M'Si in the cementum) / (total mass of the mixture B in the cementum) may preferably be between 5% and 30%, and
• the ratio (mass of NbSi 2 in the cementum) / (total mass of the mixture B in the cementum) may preferably be between 5% and 30%, and
• the ratio (mass of Nb 4 M 4 Si 7 in the cement) / (total mass of the mixture B in the cement) may preferably be between 50% and 80%.
• total mass of the mixture B in the cementum it is necessary to understand the following sum: (mass of M'Si in cementum) + (mass of NbSi 2 in cementum) + (mass of Nb 4 M ' 4 Si7 in the cementum).
• the ratio (mass of M'Si in the cementum) / (total mass of the mixture B in the cementum) may be between 5% and 30%, for example between 10% and 20%, and
• the ratio (mass of NbSi 2 in the cementum) / (total mass of the mixture B in the cementum) may be between 5% and 30%, for example between 10% and 20%, and
• the ratio (mass of Nb 4 M ' 4 Si 7 in the cement) / (total mass of the mixture B in the cement) can be between 50% and 80%.
• the cement may comprise a mixture A.
• the implementation of such a mixture advantageously makes it possible to obtain a protective coating having a very good resistance against oxidation and hot corrosion.
• the use of such a mixture makes it possible to form a protective coating comprising Nb, Cr and Si.
• several phases of the protective coating may each comprise Nb, Cr and Si.
• the cement may comprise a mixture A and M may denote Co or Ni, particularly preferably M denotes Ni.
• the cement may comprise a mixture A and x may be different from 0, in particular x may be equal to 1.
• the cement comprises a mixture A of Nb3M 3 CrSi6 and o, 6 r O , 4 Where M is Fe, Co or Ni.
• the cement may comprise a mixture A of Ti 3 M 3 CrSi 6 and M 0 , 6 Cr 0 , 4 Si where M denotes Fe, Co or Ni.
• Such a mixture makes it possible to obtain a protective coating comprising Nb, Ti and Si.
• a protective coating comprising Nb, Ti and Si.
• several phases of the protective coating, or even all of them, may each comprise Nb, Ti and of Si.
• the presence of Ti in the protective coating advantageously makes it possible to obtain a very good adaptation of the coefficients of expansion between the underlying part and the protective coating. Furthermore, the presence of Ti in the mixture A can modify the direction of growth of the protective coating and make it possible to limit the evaporation at high temperature of the Ti possibly contained in the part (this evaporation can occur by formation of titanium halides volatile during the formation of the protective coating).
• the cement comprises a mixture A of Ti 3 Fe 3 SCr 'i6 and Fe 0, 6Cr 0, 4
• the formed protective coating comprises Nb, Ti, Cr, Si and In particular, in this case, several phases of the protective coating, or all of them, may each comprise Nb, Ti, Cr, Si and Fe.
• the protective coating formed comprises Nb, Ti, Cr, Si and Co.
• several phases of the protective coating, or all of them, may each comprise Nb, Ti, Cr, Si and Co.
• the protective coating formed comprises Nb, Ti, Cr, Si and Ni.
• several phases of the protective coating, or all of them, may each comprise Nb, Ti, Cr, Si and Ni.
• the cement may comprise a mixture A and the ratio (mass (Nb x Tii -x) 3 M 3 CrSi6 in the cement before the carburization process in case) / (mass of M 0, 0 6Cr, 4 If in the cement before the start of the case hardening process) can be between 0.9 and 1.1.
• the niobium matrix may, for example, include inclusions of Nb 5 Si and / or inclusions of bs Si.
• the part may be subjected to a temperature of between 1100 ° C. and 1300 ° C. during all or part of the step of forming the protective coating.
• the duration of the case cementation process may be between 1 hour and 100 hours, for example between 2 hours and 96 hours.
• the thickness of the protective coating formed may be greater than or equal to 15 ⁇ m, for example between 15 ⁇ m and 50 ⁇ m.
• the thickness of the protective coating may be advantageous to limit the thickness of the protective coating to a value of less than or equal to 50 ⁇ m in order to avoid obtaining a fragile coating, as well as the problems of excessive spalling during thermal cycles. It may also be advantageous to produce a coating with a thickness greater than or equal to 15 ⁇ m in order to obtain satisfactory protection against oxidation.
• the invention also relates to a part comprising a refractory alloy comprising a niobium matrix in which inclusions of metal silicides are present, the surface of the part being coated with a protective coating, the protective coating comprising a phase having stoichiometry (atomic proportions ) next : - (x b -x Tii) 3M Cr Si5X £ Y where M is Fe, Co or Ni, X denotes one or more other elements may be present, x is between 0 and 1, ⁇ is between 5 and 8.5 and the sum ⁇ + ⁇ is between 3 and 7, or
• X' denotes one or more other elements possibly present
• ⁇ is between 3.2 and 4.8 and ⁇ is between 6 and 8.
• ⁇ is greater than
• Such a coated part can be obtained by implementing a method as described above.
• a method as described above is implemented to obtain the coated part according to the invention, the use of a mixture A leads to a protective coating comprising a phase (bxTii- x) r 3MpCr Si5X E and the use of a mixture B leads to a protective coating comprising a phase of Nb 4 M ' n Si 6 XV.
• coated parts according to the invention have a very good resistance against oxidation and hot corrosion.
• the protective coating is such that the phase having one of the stoichiometries indicated above is present on the outer surface of the protective coating, said outer surface being located on the opposite side to the surface of the coated part.
• X and X ' may be at least one of Al and / or Hf.
• ⁇ and ⁇ ' may be less than or equal to 1, for example 0.5, for example 0.3.
• the protective coating comprises a phase (Nb x Tii- x) 3M p Y Cr Si5X £
• silicon can be present in this phase in an atomic content of between 44% and 48%.
• the protective coating comprises a phase of b4M ' n SieX
• the silicon may be present in this phase at an atomic content of between 45% and 49%.
• phase stoichiometry of the protective coating that can be obtained within the scope of the invention are given below in Table 1.
• M can denote Co or Ni. In a particularly preferred manner, M denotes Ni.
• the protective coating may have a thickness greater than or equal to 15 ⁇ m, for example between 15 ⁇ m and 50 ⁇ m.
• the part may be a turbomachine blade.
• the part is intended to be an integral part of a combustion chamber or to constitute a distributor or a turbine ring.
• the present invention also relates to a turbomachine comprising a part as defined above.
• the present invention also relates to an aircraft comprising a turbomachine as defined above.
• FIG. 1 represents, schematically and partially, a section of a part according to the invention
• FIG. 2 schematically and partially shows a reactor that can be used for carrying out a process according to the invention
• FIG. 3 illustrates, in a simplified manner, the reaction scheme allowing the formation of a protective coating in the context of a process according to the invention
• FIGS. 4A to 4C are photographs of various protective coatings obtained on the surface of Nb ss -NbsSi3 alloys by implementing an embodiment of the method according to the invention
• FIGS. 5A to 5C are photographs of other protective coatings obtained on the surface of Nb-Si alloys by implementation of an alternative method according to the invention.
• FIG. 6 represents the results of cyclic oxidation tests at 1100 ° C. on Nb-Si parts coated with protective coatings according to the invention in comparison with an uncoated Nb-Si part.
• FIG. 1 shows a section of a part 1 coated with a protective coating 2.
• the protective coating 2 is formed on the surface S of the part 1 which comprises a niobium matrix in which inclusions of silicides metal are present.
• the thickness e of the protective coating 2 formed may, for example, be between 15 ⁇ m and 50 ⁇ m.
• the thickness e of the protective coating 2 corresponds to its largest dimension measured perpendicular to the surface S of the part 1.
• FIG. 2 shows a reactor that can be used in the context of a process according to the invention.
• this reactor is in the form of an enclosure 10 in which the part 1 to be treated is present.
• the piece 1 is present in a case 11 which comprises, on the one hand, a mixture of donor alloys 13 and, on the other hand, an activating agent 12.
• the piece 1 is, as illustrated, in contact with the case 11.
• the composition of the mixture of donor alloys 13 is chosen according to the protective coating to be obtained on the part 1.
• the mixture of donor alloys 13 may be a mixture A or a mixture B, these mixtures being defined above.
• the activating agent 12 may, for example, be chosen from: SiCl 4 , SiF 4 , NH 4 Cl, NH 4 F, metal halides such as metal fluorides or chlorides, for example CrC, and mixtures thereof.
• the donor alloys 13 and the activating agent 12 are each in the form of a powder.
• the activating agent 12 may be present in the cementum, before the start of the case cementation process, in a mass content of between 0.5% and 2% of the total mass of the mixture of donor alloys 13 in the cementum. Case carburation is carried out in the enclosure 10.
• the cementum 11 further comprises an inert diluent comprising, for example, silica (SiO 2 ) and / or alumina (Al 2 O 3 ), for example in the form of a mixture of Al 2 O 3 and SiO 2. 2 .
• the inert diluent advantageously prevents agglomeration of the cement particles on the surface of the zone to be coated during the heating of the assembly.
• the inert diluent may be present as a powder in the cement before the start of the case cementation process.
• the mass of inert diluent in the cement can, before the start of the case cementation process, be between 0.8 times and 1.2 times the total mass of the mixture of donor alloys 13 in the cement, and for example be substantially equal to the total mass of the mixture of donor alloys 13 in the cementum.
• the enclosure 10 is brought to a temperature, for example, between 1100 ° C. and 1300 ° C.
• the enclosure 10 during all or part of the process according to the invention may, for example, be filled with inert gas or be carried under primary vacuum or secondary vacuum.
• a metal halide is formed from a metal from the donor alloys and a halide from the activating agent.
• the metal halide thus formed then diffuses in the gas phase to the part 1 to be treated (step 21) on which it adsorbs (step 22).
• the metal is deposited on the surface of the piece 1 and can then diffuse within it (step 24) and the halide joins the gas phase.
• the halide diffusing in the gaseous phase can, in contact with the donor alloys, again form a metal halide and reinitiate the formation cycle of the protective coating just described. Examples
• compositions of the protective coating phases given below are given in atomic proportions.
• FIGS. 4A to 4C is a photograph of a part coated with a protective coating obtained by implementing a method according to the invention.
• the protective coatings were formed using the following B mixtures (the proportions are by weight):
• the part and the cementum are kept at a temperature of 1200 ° C. during the case cementation process and the duration of the case cementation process is 24 hours.
• the protective coatings formed comprise a plurality of distinct phases. These different phases are in the form of a stack and are superimposed with each other.
• stage denoted "1” corresponds to Nb 27 C026,9S ⁇ 45,9 7
• stage “2” corresponds to the six o b
• stage denoted "3" corresponds to Nb 6 2.7Si36.7.
• the stage denoted "1" corresponds to the Nb32,6Nio, 2SÎ67,3
• the stage denoted “2” corresponds to the Nb29,3N i25,3Si 45, 4
• denoted by the stage “3” corresponds to the Nb 40
• 3Ni9,7,7Si39,9 corresponds to Nb 6 2,7Si37,2.
• FIGS. 5A to 5C is a photograph of a part coated with a protective coating obtained by implementing a method according to the invention.
• the protective coatings were formed by using the mixtures A detailed in Table 2 below in the column “Donor alloys”).
• the contents of the alloys donors are mass contents.
• the chemical nature of the phases obtained in the protective coating are specified in the column "Composition Probe of the analyzed phases”.
• the duration of the case cementation process is 24 hours and the part and the cementum are maintained at 1200 ° C during the case cementation process.
• the service life of the parts protected by these coatings is improved compared to the bare part (i.e. without coating).
• the tests were doubled for each of the coatings in order to prove the reproducibility of the results obtained.
• the most efficient coatings resist about 3000 oxidation cycles at 1100 ° C. Under cyclic conditions, these coatings have good resistance to oxidation up to 1200 ° C.
• these protective coatings on niobium-based parts can advantageously make it possible to divide by 200 the taps recorded during an isothermal exposure at 1100 ° C. And in isothermal condition, these coatings can advantageously confer effective protection up to 1300 ° C.

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• 2014
  • 2014-12-03 FR FR1461850A patent/FR3029535B1/fr active Active
• 2015
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